JP2012074148A - Light-emitting device and lighting fixture equipped with the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To joint a circuit board and a heat-radiating member in adhesion for a light-emitting device without using an adhesive, and yet, to enhance a radiation effect of heat generated at a solid light-emitting element.SOLUTION: The light-emitting device 1 is provided with a circuit board 4 with an LED chip 3 mounted on the surface, a fixture body 5 as a heat-radiating member fitted on a rear face of the circuit board 4, and a heat sink 7 attached to a surface of the circuit board 4. The heat sink 7, provided with an opening 71 for exposing a projection face of the LED chip 3, is locked to the fixture body 5 with a screw 8. The heat sink 7 presses the circuit board 4 down to the fixture body 5, in a state locked to the fixture body 5. Here, the circuit board 4 is pinched between the heat sink 7 and the fixture body 5, so that the circuit board 4 can be adhered to the fixture body 5 and the heat sink 7 to facilitate the mounting work. Further, since the surface side of the circuit board 4 can efficiently radiate heat through the heat sink 7, heat radiation characteristics of the LED are improved.

Description

  The present invention relates to a light-emitting device using a solid-state light-emitting element such as a light-emitting diode (LED), and a lighting fixture including the same.

  Conventionally, in this kind of light-emitting device, a circuit board having an LED element mounted on the surface and a heat radiating member provided on the back surface of the circuit board are used to dissipate heat generated by light emission of the LED element through the heat radiating member. Is known (see, for example, Patent Document 1).

JP 2007-287751 A

  By the way, in the light emitting device as described above, a flexible printed circuit board (FPC) having high versatility is used for the circuit board. However, since the FPC has low rigidity, an adhesive is used for the circuit board and the heat dissipation member. Are joined. At this time, in order to join the circuit board and the heat radiating member so as not to generate thermal resistance, it is necessary to press and bond the entire surface of the board to the heat radiating member with a uniform force using a jig. It was over. Further, the surface side of the circuit board can only release heat directly to the surrounding atmosphere (air layer), and the LED element heat cannot be sufficiently radiated.

  The present invention has been made to solve the above-described problem, and allows the circuit board and the heat radiating member to be closely bonded to each other without using an adhesive, and further, the heat generated in the solid state light emitting device. It is an object of the present invention to provide a light emitting device capable of enhancing a heat dissipation effect and a lighting fixture including the light emitting device.

  The light-emitting device of the present invention is a light-emitting device including a circuit board on which a solid light-emitting element is mounted. The first heat dissipating member provided on the back surface of the circuit board and the surface of the circuit board are attached. A second heat radiating member having an opening that exposes a light projecting surface of the light emitting element; and a locking member that locks the second heat radiating member to the first heat radiating member. The member is clamped between the first heat radiating member by pressing the circuit board against the first heat radiating member in a state where the member is locked to the first heat radiating member by the locking member. It is characterized by doing.

  In this light-emitting device, it is preferable that the opening of the second heat radiating member is formed so that the opening area is widened in the light extraction direction, and the inner peripheral surface of the opening is a reflective surface.

  In this light emitting device, it is preferable that an optical member for diffusing or condensing light from the solid light emitting element is disposed in the opening of the second heat radiating member.

  The lighting fixture of this invention was equipped with said light-emitting device.

  According to the light emitting device of the present invention, the circuit board can be sandwiched between the first and second heat radiating members, and the circuit board can be brought into close contact with the heat radiating members, so that the circuit board and the heat radiating member are bonded together. Eliminates the need for easy installation. Moreover, since the surface side of the circuit board can efficiently release heat through the second heat dissipation member, the heat dissipation characteristics of the LED can be improved.

The external view which looked at the state which mounted | wore the lighting fixture provided with the light-emitting device which concerns on one Embodiment of this invention on the ceiling from the downward direction. The partial cross section side view of the lighting fixture. The perspective view which looked at the light emission side of the said light-emitting device from upper direction. The sectional side view of the circuit board which mounted the LED chip of the light-emitting device. (A) is a sectional side view in the state which mounted the circuit board in the instrument main body, (b) is a sectional side view in the state which locked the heat sink to the instrument main body with the bis | screw. The perspective view which shows the other structure of the light-emitting device. The sectional side view which shows other structure of the light-emitting device. The sectional side view which shows other structure of the light-emitting device.

  A light emitting device according to an embodiment of the present invention will be described with reference to FIGS. 1 to 3, the light emitting device 1 is mounted on a lighting fixture 2. The lighting fixture 2 is a downlight type lighting fixture and is used by being embedded in a ceiling portion of a building such as an office or a factory. The light emitting device 1 includes a circuit board 4 on which an LED chip 3 (solid light emitting element) is mounted, and a thermally conductive instrument body 5 (first heat radiating member) that holds the circuit board 4. The instrument main body 5 is attached to the back surface of the circuit board 4 as a heat radiating portion, and dissipates heat generated from the LED chip 3. The instrument body 5 includes a reflector 6 that reflects the light emitted from the LED chip 3.

  The light emitting device 1 includes a heat radiating plate 7 (second heat radiating member) attached to the surface of the circuit board 4 and screws 8 (locking members) for locking the heat radiating plate 7 to the instrument body 5. Here, the lighting fixture 2 has a holding tool 10 for fixing the fixture to the ceiling 9, and when the fixture is inserted into the mounting hole 9 a of the ceiling 9, the peripheral edge of the mounting hole 9 a is clamped by the holding fixture 10. It has become. The holder 10 is provided at an outer edge portion of the light emitting side of the reflecting plate 6.

  The LED chip 3 is formed of a substantially square chip, and is disposed in the center of the surface of the circuit board 4 here. The number of LED chips 3 is not particularly limited, and may be singular or plural. For example, an LED package that emits white light can be used as the LED chip 3. In this case, a blue LED element in which a phosphor that converts the wavelength of blue light into yellow light is sealed. The emission color of the LED chip 3 is not limited to white, and may be yellow or orange, for example.

  The circuit board 4 is composed of a flexible printed circuit board (FPC), and here, a disk-shaped one is used. The FPC used for the circuit board 4 preferably has a thickness of 250 μm or less when the conductive part to the LED chip 3 has a single layer structure, and preferably has a thickness of 500 μm or less when the conductive part has a multilayer structure. If such an FPC is used, the board can be flexibly arranged along the installation surface, so that the circuit board 4 and the instrument body 5 are brought into contact with each other without interposing an air layer to reduce the thermal resistance at these boundary surfaces. It becomes possible to do. The circuit board 4 is not limited to the FPC, and for example, an aluminum board or an FR board can be used. A cover 4 a (see FIG. 2) that protects the LED chip 3 may be provided on the surface side of the circuit board 4.

  The instrument body 5 is formed using a member having excellent heat dissipation, such as aluminum or copper. When an aluminum material is used for the instrument body 5, an aluminum die casting method can be used as a method for forming the instrument body 5. The instrument body 5 is composed of a housing having a substantially frustoconical outer shape, and the bottom 51 serves as a mounting surface of the circuit board 4. A screw hole for the screw 8 is formed in the bottom 51 of the instrument body 5. A plurality of heat dissipation fins 52 are provided on the outer periphery of the instrument body 5. A power supply device 11 for lighting the LED chip 3 is provided on the top plate portion 53 of the instrument body 5, and the power supply device 11 is connected to the circuit board 4 by the power supply line 12.

  The heat sink 7 has an opening 71 that exposes the light projecting surface of the LED chip 3. The heat radiating plate 7 is made of a material having high thermal conductivity, for example, an aluminum plate, and has a larger outline in plan view than the circuit board 4. The material used for the heat sink 7 is not limited to a metal such as aluminum, but may be a resin material mixed with a heat conductive metal filler. The heat radiating plate 7 has a through hole through which the screw 8 passes in a portion outside the outline of the circuit board 4 in plan view. The heat sink 7 is exposed to the fixture body 5 by screws 8, exposes the LED chip 3 from the opening 71, presses the circuit board 4 against the fixture body 5, and the circuit board between the fixture body 5 and the heat sink 7. 4 is pinched. The mounting of the radiator plate 7 and the circuit board 4 to the instrument body 5 is not limited to the above-described configuration. A screw through hole is formed in the circuit board 4, and the radiator plate 7 is engaged with the instrument body 5 through the circuit board 4 by screws 8. It may stop.

  As shown in FIG. 4, the circuit board 4 uses a base 41 made of an insulating resin film, a copper foil layer 42 formed on the base 41, and an adhesive layer 43 on the copper foil layer 42. And an insulating layer 44 formed as a coating. The base material 41 is comprised with a polyimide film, for example. The copper foil layer 42 is a circuit pattern for supplying power to the LED chip 3, and is electrically connected to the electrode portion 31 of the LED chip 3 through the through hole 45. The insulating layer 44 is made of, for example, polyimide resin, and is formed from the upper surface of the substrate 4 to the end surface portion. By using such a circuit board 4, it is possible to easily ensure insulation between the circuit board 4 and other components (the instrument body 5, the heat sink 7, etc.) as compared with a general-purpose aluminum board or FR board. In particular, when the heat radiating plate 7 is formed of a resin material to which a metal filler is added, the heat radiating plate 7 has high conductivity. Therefore, it is preferable that the end face of the substrate secures insulation as described above.

  Next, a procedure for attaching the circuit board 4 and the heat sink 7 to the fixture body 5 in the light emitting device 1 configured as described above will be described with reference to FIG. First, as shown in FIG. 5A, the circuit board 4 on which the LED chip 3 is mounted is placed on the attachment surface of the bottom 51 of the instrument body 5. At this time, if an adhesive layer is interposed between the circuit board 4 and the instrument body 5, the thermal resistance between the circuit board 4 and the instrument body 5 can be reduced. This adhesive layer is not necessarily provided, and may be appropriately used according to the specification of the instrument. Next, the heat sink 7 is disposed on the circuit board 4 through the LED chip 3 through the opening 71, and the screws 8 are passed through the through holes of the heat sink 7 as shown in FIG. I do. By this tightening, the circuit board 4 is pressed against the instrument body 5 by the heat radiating plate 7 with an equal force, and is sandwiched between the circuit board 4 and the instrument body 5.

  As described above, according to the light emitting device 1 according to the present embodiment, the circuit board 4 can be sandwiched between the fixture body 5 and the heat radiating plate 7 and the circuit board 4 can be brought into close contact with the fixture main body 5 and the radiating plate 7. The circuit board 4 does not need to be joined by bonding as in the prior art, and the mounting operation is facilitated. Moreover, since the surface side of the circuit board 4 can efficiently release heat through the heat dissipation plate 7, the heat dissipation characteristics of the LED can be improved.

  Next, another configuration example of the light emitting device 1 will be described with reference to FIG. In the light emitting device 1, the heat radiating plate 7 includes heat radiating fins 72. The fins 72 are disposed on the surface of the heat radiating plate 7 opposite to the circuit board 4. The fins 72 may be formed integrally with the heat sink 7 or may be formed separately from the heat sink 7. According to the light emitting device 1, the heat release capability of the heat radiating plate 7 is increased, and the heat generated from the LEDs can be efficiently radiated.

  Next, still another configuration example of the light emitting device 1 will be described with reference to FIG. In the light emitting device 1, the opening 71 of the heat radiating plate 7 is formed so that the opening area widens in the light extraction direction, and the inner peripheral surface of the opening 71 is a reflecting surface. In order to form such an opening 71, the radiator plate 7 has a larger thickness than that described above.

  According to the light emitting device 1, the light emitted from the LED chip 3 can be reflected by the inner peripheral surface of the opening 71 and can be arbitrarily distributed. For example, the light extraction efficiency of the light emitting device 1 is improved. Can do.

  Next, still another configuration example of the light emitting device 1 will be described with reference to FIG. The light emitting device 1 has a light-transmitting optical member 13 that diffuses or collects light from the LED chip 3 in the opening 71 of the heat sink 7. The optical member 13 has a shape along the inner peripheral surface of the opening 71 and is disposed so as to cover the upper side of the LED chip 3. For the optical member 13, for example, various lens bodies such as a diffusion lens and a condensing lens, a light diffusion plate, and the like can be used.

  According to the light emitting device 1, the light emitted from the LED chip 3 can be arbitrarily distributed by the optical member 13, and the usage application to the lighting fixture can be expanded. In addition, here, the opening 71 of the heat radiating plate 7 is shown widening in the light deriving direction. However, the present invention is not limited to this. For example, the inner peripheral surface of the opening 71 is not inclined (see FIG. 5), and the optical member 13 may be arranged in the opening 71. Moreover, it does not ask | require whether the internal peripheral surface of the opening part 71 of the heat sink 7 is a reflective surface.

  In addition, this invention is not restricted to the structure of the said embodiment, A various deformation | transformation is possible in the range which does not change the meaning of invention. For example, although the example which comprised the instrument main body 5 as a heat radiating member was shown above, it is not restricted to this, You may make it provide a heat radiating member separately from the instrument main body 5. FIG.

DESCRIPTION OF SYMBOLS 1 Light-emitting device 2 Lighting fixture 3 LED chip (solid-state light emitting element)
4 Circuit board 5 Instrument body (first heat dissipation member)
7 Heat dissipation plate (second heat dissipation member)
71 opening 72 fin 8 screw (locking member)
13 Optical members

Claims (4)

In a light emitting device including a circuit board on which a solid light emitting element is mounted,
A first heat dissipating member provided on the back surface of the circuit board;
A second heat dissipating member attached to the surface of the circuit board and having an opening for exposing a light projecting surface of the solid state light emitting device;
A locking member for locking the second heat radiating member to the first heat radiating member,
The second heat radiating member presses the circuit board against the first heat radiating member in a state in which the second heat radiating member is locked to the first heat radiating member by the locking member. A light-emitting device characterized by being sandwiched between the two.   2. The opening of the second heat radiating member is formed so that an opening area is widened in a light leading direction, and an inner peripheral surface of the opening is a reflecting surface. Light-emitting device.   The light-emitting device according to claim 1, wherein an optical member that diffuses or collects light from the solid-state light-emitting element is disposed in the opening of the second heat radiating member.   A lighting fixture comprising the light emitting device according to any one of claims 1 to 3.

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